Recently, the most widely used rolls for hot rolling mills, have been composite type rolls composed of an outer shell and a core material. The conventional method of producing these rolls is centrifugally casting technique, where the shell metal is first poured into the rotating mold then the core metal is added to the mold after shell solidification. Usually, wear resistant cast iron such as nickel-chromium alloyed grain iron (Ni-G) or high chromium iron (Hi-Cr) precipitating cementaite type carbide is used for the shell material, and gray iron or ductile iron is used for the core material.
For a demand for more severe rolling condition and for improvement of productivity in rolling, a roll having higher wear resistance and crack resistance has been required.
In view of such circumstance. Japanese Unexamined Patent Publication (Kokai) No. 60-124407 and Japanese Unexamined Patent Publication(Kokai) No. 61-177355 propose application of high Vanadium (V) iron for the shell material of the centrifugal cast roll.